1. Field of the Invention
This invention relates to an apparatus for infusing liquid medication and, more particularly, to a liquid medication infusing apparatus which includes liquid feeding means for infusing liquid medication into a living body, the quantity of liquid medication infused conforming to a control signal, means for generating time information, and a control circuit connected to the time information generating means for producing control signals.
2. Description of the Prior Art
There have been numerous disclosures concerning the medication infusing apparatus of the above-described type, particularly for the infusion of insulin in the treatment of diabetics. One example of such a previously disclosed apparatus infuses the insulin on the basis of pre-programmed quantities. In other words, a schedule of the patient's daily activities is standardized or set beforehand, and a program is prepared according to which the insulin dose is increased or decreased with time in accordance with the set schedule. For instance, since there is a rise in the blood sugar level during meals, the insulin dose is programmed to increase three times per day during each mealtime. However, many diabetics lead active social lives and do not always take their meals at the designated hour. Accordingly, the infusion of the programmed insulin dose at the programmed time can result in an overdose and expose the patient to the danger of an abnormally low blood sugar level.
One proposed solution to the above problem is a system which constantly infuses a fixed, minimum required dose of the insulin and which comes equipped with a button that the patient depresses when he wishes to consume a meal. Depressing the button starts a predetermined sequence in accordance with which the insulin dose is changed to supplement the fixed dose. With this system, however, the quantity of insulin infused under ordinary conditions is constant throughout the day irrespective of the time. The patient's activity, on the other hand, generally changes from one occasion to the next. Thus, even if the problem of insulin dose during meals is solved, the constant or basic insulin dose at other times should be different to conform to the rhythm of the patient's daily activities. For example, the required insulin dose during the daytime when the patient is active differs from the dose required at night when the patient is at rest or asleep. Another important factor is that the pattern of insulin infusion generally differs according to the length of each meal. In other words, the sequence through which the infused insulin dose varies is not the same for the breakfast, lunch and supper meals. Since a patient may miss or skip a meal for some reason or take a meal at other than the designated hour, there is a need for means which can take such occasions into account and infuse the insulin dose best suited for the patient's physiological needs at that time. Another requirement for such means is that it be capable of immediately restoring the ordinary insulin dose, or basic pattern, if the patient should operate the device incorrectly or at the wrong time or if, after having initiated the infusion of an insulin dose required for the duration of a meal, the patient should interrupt or be forced to miss that meal for some reason.